The present invention relates to a self-propelled stairs moving unit going up and down the stairs of a station, public facilities or the like, traveling by the power of a driving source, putting a wheelchair or a baggage thereon. Especially, the present invention relates to the self-propelled stairs moving unit having crawler traveling units wherein a pallet can be held to be level, especially the pallet can be held to be level when the angle of the crawler traveling portion is rapidly changed at the upper end or the lower end of the stairs, and stable travel with small type is possible.
As a stairs moving unit for going the stairs up and down, putting a wheelchair on which a person rides is disclosed in the gazette of the Japanese patent application (First publication Number: Tokukaihei 6-278665). The stairs moving unit has a self-propelled body having crawler traveling units driven by a driving motor, and a pallet rotatably supported by the rear end portion of the self-propelled body with an axis in its front and rear portions. Besides, a holding handle is provided with the pallet, and a motor cylinder is provided between the pallet and the self-propelled body. When the stairs moving unit is moved on a flat face, the motor cylinder is set at a shrinkage position so as to hold the self-propelled body and the pallet in parallel, and the casters and the wheels provided with the pallet are contacted with the ground so as to travel the stairs moving unit. When the stairs moving unit is moved up and down the stairs, it travels with the driving motor in the state that the motor cylinder is extended and the face contacting ground of the cralwer is contacted with the ground more than two steps of the stairs and the self-propelled body is inclined along the inclination of the stairs, and then the pallet is held to be almost level.
Furthermore, the stairs moving unit has guide wheels projecting from the self-propelled body to the side. Then, the self-propelled body is stably traveled in such a manner that the guide wheel is inserted into the guide rail provided with the side portion of the stairs at the time of traveling the stairs moving unit up and down.
On the other hand, as shown in the gazette of the Japanese patent application (First publication number: Tokukaihei8-80879), a traveling unit for traveling on a rapid inclined place, having a pair of crawler traveling units on the right and left sides of the unit respectively is proposed. This type of unit has an upper rotating body which a work machine, such as a hydraulic shovel, is built in, support frame rotatably supporting the rotating body, and four crawler traveling units on the right and left, in which the front and rear units are a pair. The front crawler traveling units are connected with the front portion of the support frame, free to oscillate, and the support frame and the rear crawler traveling unit are connected with the connection pin provided with both end portions of the connection link, free to oscillate, and an oscillating jack is provided between the connection link and the rear end portion of the support frame.
The traveling unit for traveling on a rapid inclined place travels on a rapid inclined place in such a manner that the power from the engine provided with the work machine is transferred to the four crawler traveling units. Besides, the support frame, which front portion is supported by the front crawler traveling unit free to oscillate, is held to be almost level by the oscillating jack to be shrunk and extended on the basis of the signal from a level sensor.
Although the pallet putting a wheelchair or the like on can be held to be almost level when the above-mentioned stairs moving unit is traveled on a flat place or on the stairs having a predetermined inclined angle, the motor cylinder does not follow the rapid angular change of the self-propelled body when the stairs moving unit is traveled from a flat face to the stairs or from the stairs to a flat face. Then, the person on the wheelchair feels some misgivings by rapidly facing downward or upward.
Especially, when the stairs moving unit is traveled down the stairs from a flat face on the upper most step of the stairs, the crawler traveling unit is changed in its angle from the level state to the inclination of the stairs in a moment after its load center goes over the corner portion of the uppermost step. On this occasion, the person on the wheelchair is turned, facing downward in a moment by also facing the wheelchair to the forward, and the person strongly feels mental fears. Even if the guide wheel is inserted into the guide rail, the above-mentioned rapid angular change of the pallet can not be saved although an operator can stably operate, preventing the self-propelled body from slipping in lateral direction as long as the guide wheels are located on only one side so as not to support the load.
Besides, it is necessary to always position the holding handle which an operator hands on the upper side of the stairs in the stairs moving unit. For this reason, the person on the wheelchair feels that he may be turned so as to drop from the wheelchair when the unit goes down. Besides, when the unit goes up the stairs, the person on the wheelchair faces the backward and feels that he is turned in the upper direction at the upper end of the stairs, and feels physical disorder since he faces ordinary people going up the stairs.
On the other hand, the angular change of the support body of the rapid inclined place traveling unit having four crawler traveling units is smaller than one having each one crawler unit in right and left when the inclined angle is changed. Since the support frame is supported by the connection pins (the third oscillating connection portion) provided with the position projecting to the side hand and the upper hand from the truck frame of the front crawler traveling unit through brackets, when the front crawler traveling unit goes over the uppermost portion of the inclination (for instance, the corner portion of the uppermost portion of the stairs) and its angle is widely changed, the connection pins are moved, the support frames are moved forward and backward, and upward and downward. Then, it is difficult to maintain the work machine to be level so as to stably travel.
The above-mentioned stairs moving unit goes up and down, hooking the lug of rubber crawler on the corner portion of each step along the inclination of the stairs. But, the lug of the crawler is not hooked on the corner portion of the stairs when the stairs is wet or the travel direction of the crawler traveling unit and the stairs are not crossed at a right angle, then the crawler traveling unit is slipped and traveled obliquely, or the moving unit may face laterally. Although the moving unit can be prevented from facing laterally by inserting the guide wheel into the guide rail, the slip of the crawler traveling unit can not be saved, then it is not sufficient concerning the stable travel of the moving unit.
Besides, it is necessary that a longer rubber crawler traveling unit, which ground contacting face bridges at least two steps of the stairs, is provided and a inclined travel face having the height of one step or more of the stairs is provided. Then, the crawler traveling unit is made big.
Furthermore, since the relatively long crawler traveling unit is necessary, when the crawler traveling unit is transferred from a flat face to the stairs or from the stairs to a flat face, the angle of the crawler traveling unit is rapidly changed similar to the above-mentioned after the center of gravity of its load goes over the above-mentioned transfer point. Then, the motor cylinder can not follow the rapid angular change of the self-propelled body. The person on the wheelchair feels fears by rapidly facing downward or upward.
On the other hand, when the rapid inclined place traveling unit having four crawler traveling units is used for going the stairs up and down, the lug of the crawler is not hooked on the stairs and the crawler traveling unit may slip, in a similar way to the above-mentioned stairs moving unit. Taking such a state into consideration that concerning the four crawler traveling units, one of the front or the rear crawler traveling units is on the stairs and the other is on a flat face, two steps or more length of crawler ground contacting face is necessary in order to stably travel each crawler traveling unit, and furthermore, the inclined travel face of one step or more height of the stairs is necessary on the front hand of each crawler traveling unit. Then, it is not avoidable to make the unit large-sized.